Reassessment of circadian profile of blood pressure and heart rate in diabetic patients with autonomic neuropathy.
Previous studies have shown that the normal circadian blood pressure fall is absent in patients with diabetic autonomic neuropathy, while the reported rise in blood pressure during the night in the same patients is controversial. This study analyzed the circadian profile in 19 diabetic patients with established autonomic neuropathy. Twenty-four hour ambulatory systolic blood pressure, diastolic blood pressure, mean arterial pressure, and heart rate were recorded every 20 minutes during the day and every 60 minutes at night in 29 patients, 19 with diabetic autonomic neuropathy and 10 nondiabetic hypertensive patients as controls. Twelve diabetic patients with autonomic neuropathy with unknown hypertension were found to have hypertension based on 24 hour ambulatory blood pressure monitoring. Repeated measured analysis of variance (ANOVA) and trend analysis indicated that the linear systolic blood pressure increased from night to morning to afternoon while mean arterial pressure and diastolic blood pressure increased from night to morning but decreased from morning to afternoon. In practice, the early morning rise in systolic blood pressure in diabetic neuropathy is not different from that in normal or hypertensive patients and requires appropriate treatment. The absence of the nocturnal rise in the blood pressure revealed a subgroup of patients with diabetic neuropathy which demonstrated no fatal cardiovascular or renal events over 18 to 24 months of follow-up.